The binutils 2.24 introduces some changes for MIPS16 and microMIPS that break debugging with GDB 7.6.1 (compared to binutils 2.23).
http://www.sourceware.org/ml/gdb-patches/2013-11/msg00651.html
A GDB 7.6.2 release should be created to help users switching to binutils 2.24 have an official release they can use. And for the record, GDB 7.7 will also support binutils 2.2.4